<template>
  <div class="s-canvas">
    <canvas
      class="rounded-sm"
      id="s-canvas"
      :width="contentWidth"
      :height="contentHeight"
    ></canvas>
  </div>
</template>

<script setup lang="ts">
import { onMounted, watch } from "vue";

name: "SIdentify";
/**
 * props参数说明
 *
 * @param identifyCode 显示的验证码
 * @param fontSizeMin 显示的验证码的字体最小字体
 * @param fontSizeMax 显示的验证码的字体最大字体
 */
const props = defineProps({
  identifyCode: {
    type: String,
    default: "1234",
  },
  fontSizeMin: {
    type: Number,
    default: 26,
  },
  fontSizeMax: {
    type: Number,
    default: 30,
  },
  backgroundColorMin: {
    type: Number,
    default: 255,
  },
  backgroundColorMax: {
    type: Number,
    default: 255,
  },
  colorMin: {
    type: Number,
    default: 0,
  },
  colorMax: {
    type: Number,
    default: 160,
  },
  lineColorMin: {
    type: Number,
    default: 100,
  },
  lineColorMax: {
    type: Number,
    default: 255,
  },
  dotColorMin: {
    type: Number,
    default: 0,
  },
  dotColorMax: {
    type: Number,

    default: 255,
  },
  contentWidth: {
    type: Number,
    default: 110,
  },
  contentHeight: {
    type: Number,
    default: 30,
  },
});
// 生成一个随机数
function randomNum(min: number, max: number) {
  return Math.floor(Math.random() * (max - min) + min);
}
// 生成一个随机的颜色
function randomColor(min: number, max: number) {
  let r = randomNum(min, max);
  let g = randomNum(min, max);
  let b = randomNum(min, max);
  return "rgb(" + r + "," + g + "," + b + ")";
}
function drawPic() {
  let canvas: any = document.getElementById("s-canvas");
  let ctx: any = canvas.getContext("2d");
  ctx.textBaseline = "bottom";
  // 绘制背景
  ctx.fillStyle = randomColor(props.backgroundColorMin, props.backgroundColorMax);
  ctx.fillRect(0, 0, props.contentWidth, props.contentHeight);
  // 绘制文字
  for (let i = 0; i < props.identifyCode.length; i++) {
    drawText(ctx, props.identifyCode[i], i);
  }
  drawLine(ctx);
  drawDot(ctx);
}
function drawText(ctx: any, txt: any, i: any) {
  ctx.fillStyle = randomColor(props.colorMin, props.colorMax);
  ctx.font = randomNum(props.fontSizeMin, props.fontSizeMax) + "px SimHei";
  let x = (i + 1) * (props.contentWidth / (props.identifyCode.length + 1));
  let y = randomNum(props.fontSizeMax, props.contentHeight - 5);
  var deg = randomNum(-45, 45);
  // 修改坐标原点和旋转角度
  ctx.translate(x, y);
  ctx.rotate((deg * Math.PI) / 180);
  ctx.fillText(txt, 0, 0);
  // 恢复坐标原点和旋转角度
  ctx.rotate((-deg * Math.PI) / 180);
  ctx.translate(-x, -y);
}
function drawLine(ctx: any) {
  // 绘制干扰线
  for (let i = 0; i < 5; i++) {
    ctx.strokeStyle = randomColor(props.lineColorMin, props.lineColorMax);
    ctx.beginPath();
    ctx.moveTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight));
    ctx.lineTo(randomNum(0, props.contentWidth), randomNum(0, props.contentHeight));
    ctx.stroke();
  }
}
function drawDot(ctx: any) {
  // 绘制干扰点
  for (let i = 0; i < 80; i++) {
    ctx.fillStyle = randomColor(0, 255);
    ctx.beginPath();
    ctx.arc(
      randomNum(0, props.contentWidth),
      randomNum(0, props.contentHeight),
      1,
      0,
      2 * Math.PI
    );
    ctx.fill();
  }
}
watch(
  () => props.identifyCode,
  (n: string, o: string) => {
    if (n) {
      drawPic();
    }
  },
  { deep: true }
);
onMounted(async () => {
  await drawPic();
});
</script>

<style lang="scss" coped>
.s-canvas {
  height: 100% !important;
}
.s-canvas canvas {
  margin-top: 1px;
  margin-left: 8px;
}
</style>
